Clocking solutions for SFQ circuits

Living on the verge of the IoT era, the entire world is excited about the potential of mining the monumental amounts of data that would become available in the near future. However, this abundance of data requires supercomputers faster and more powerful than ever that do not require a neighboring nuclear plant for power! ❧ Single Flux Quantum (SFQ) technology has the potential to meet the booming demands for lower power consumption and higher operation speeds in the electronics industry and future exascale supercomputing systems. Nevertheless, the promised benefits of three orders of magnitude lower power at an order of magnitude higher performance have yet to be attained. In particular, ultra-high-speed clocking of large scale SFQ circuits in the presence of unprecedented levels of timing uncertainties represents a tough obstacle for the technology to advance. In this thesis, we propose an innovative self-adaptive clocking technique which is designed to be resilient in such uncertain environments. Our proposed hierarchical chains of homogeneous clover-leaves clocking, (HC)²LC, inherits its robustness from spatially correlated cell delays and from the timing robustness of the SFQ traditional counter-flow clocking. ❧ Our simulations show that averaging over the ISCAS'85 benchmark circuits, at the same speed, and with only an area overhead of 9.00%, (HC)²LC achieves 52.3% and 211.8% yield improvement over zero-skew trees at low and medium ranges of σ of gate delays, respectively.